3t2 THE ZOOLOGIST. 



them for some localities, as for Norfolk by the Marsham family, 

 so far back as 1736. In recent years these observations have 

 been carried out on a larger and more systematic scale, by 

 MiddendorfF, who, forty years ago, devoted himself to the study 

 of the lines of migration in the Russian Empire, tracing what he 

 called the isopipteses, the lines of simultaneous arrival of parti- 

 cular species, and by Professor Palmen, of Finland, who, twenty 

 years later, pursued a similar course of investigation; and by 

 Professor Baird on the migration of North American birds ; and 

 subsequently by SevertzofF as regards Central Asia, and Menzbier 

 as regards Eastern Europe. As regards our own coasts, a vast 

 mass of statistics has been collected by the labours of the 

 Migration Committee appointed by the British Association in 1880, 

 for which our thanks are chiefly due to the indefatigable zeal of 

 Mr. J. Cordeaux, and his colleague Mr. J. A. Harvie Brown, 

 the originators of the scheme by which the lighthouses were for 

 nine years used as posts of observation on migration. The 

 reports of that Committee are familiar to us, but the inferences 

 are not yet worked out. I cannot but regret that the Committee 

 has been allowed to retire. Professor W. W. Cooke has been 

 carrying on similar observations in the Mississippi Valley, and 

 others, too numerous to mention, have done the same elsewhere. 

 But, as Professor Newton has truly said, all these efforts may be 

 said to pale before the stupendous amount of information amassed 

 during more than fifty years by the venerable Herr Gatke of 

 Heligoland, whose work we earnestly desire may soon appear in 

 an English version. 



We have, through the labours of the writers I have named, 

 and many others, arrived at a fair knowledge of the When ? of 

 migration. Of the How ? we have ascertained a little, but very 

 little. The lines of migration vary widely in different species, 

 and in different longitudes. The theory of migration being 

 directed towards the magnetic pole, first started by Middendorff, 

 seems to be refuted by Baird, who has shown that in North 

 America the theory will not hold. Yet, in some instances, there 

 is evidently a converging tendency in northward migrations. The 

 line, according to Middendorff, in Middle Siberia is due north, in 

 Eastern Siberia S.E. to N.W., and in Western Siberia from S.W. 

 to N.E. In European Russia Menzbier traces four northward 

 routes ; (1) A coast line coming up from Norway round the North 



